Add rules.mk containing default rules.

Add comment for DELETE macro

src/build/Common.gmake

@@ -52,6 +52,7 @@
 #					  different options of the same source file				#
 #																			#
 # Common Build Macros Defined:												#
+#  DELETE			- Delete files (Preferrably verbose)					#
 #  OBJODIR			- Object output dir										#
 #  LIBODIR			- Library output dir									#
 #  EXEODIR			- Executable output dir									#

src/build/rules.mk

+$(OBJODIR):
+	$(QUIET)$(IFNOTEXIST) mkdir $(OBJODIR)
+
+$(LIBODIR):
+	$(QUIET)$(IFNOTEXIST) mkdir $(LIBODIR)
+
+$(EXEODIR):
+	$(QUIET)$(IFNOTEXIST) mkdir $(EXEODIR)
+
+clean:
+	@echo Deleting $(OBJODIR)$(SLASH)
+	$(QUIET)$(DELETE) $(OBJODIR)$(SLASH)*
+	@echo Deleting $(LIBODIR)$(SLASH)
+	$(QUIET)$(DELETE) $(LIBODIR)$(SLASH)*
+	@echo Deleting $(EXEODIR)$(SLASH)
+	$(QUIET)$(DELETE) $(EXEODIR)$(SLASH)*